Boiler-tube construction



Aug. 31 1926.

FIG. WILCOTT BOILER TUBE CONSTRUCTION Filed July '7, 1925 INVENJYOR M$1M BY 7% 7 A TTORNEY Patented Aug. 31, 1926.

Ut tlll'ED STATES FREDERICK G, WILCOT'I, OF SAN: QUENTIN, CALIFORNIA.

BOILER-TUBE CONSTRUCTION.

Application filed July 7, 1925. Serial No. 41,955.

My invention relates to boiler tubes and g has particular reference toboiler tube construction for fire tube boilers, and to a lesser degreeto the tubes of water tube boilers.

Present tubes for steam boilers are of.

uniform thickness throughout, the fire passing therethrough impinges onthe walls of the tube and with greater impingement on the top wall. Thisunequal heating of the top and bottom wall, sets up unequalstresses inthe tube which eventually may equalize,

but it is well'known that tubes and boiler heads fracture owing toover-stressed areas beyond the elastic limit of the metal. 'Also firetubes are prone to burn out along the top area and official inspectionoftenre quiresthat defective tubesbe removed and replaced by new ones.

An'important object of my invention is to overcome the abovedeficiencies by the provision of a liner to be positioned in the tubesand of a design to correct the above inequalities, increase the life ofthe tubes and likewise the boiler, and reduce the danger of the boilerfracturing at the tubes and heads to a minimum.

Another object is to consider the great number of boilers in use todayand so manufacture my liner that the same can be applied thereto, andthat liners can be carried in stock to meet the standard sizes of boilertubes.

Another object is to meet the problem of future boilers, that is, beforeor after the boiler is built my invention can be applied to the tubesthereof. Also, for future tubes my liner may be incorporated with thetube in its manufacture as a homogeneous unit, but according to thepresent day process of manufacturing tubes I would conclude that itappears uneconomical to do so at th1s time.

lVith the above and other objects in. view I will exemplify one form ofmy invention by the illustration shown in the accompanying drawing inwhich Figure 1 is a perspective view of the invention per se forexisiting boilers.

Figure 2 is a transverse cross-section of a standard boiler tube with aliner therein in normal position; and

Figure 3 is a longitudinal vertical section through a portion of ahorizontal fire tube steam boiler; a portion of one of the tubes isshown in full.

jAdverting to the figures of the drawing I 'will ow describe theinvention in detail:

The ,numeral 4 indicates the liner of my tube construction andthroughout the figures it is shown crescent-shaped in transversecross-section, however, other segmental shapes are to be consideredwithin of my improvement and as per the scope of the claims followingthis specification.

5 isthe ordinary boiler tube of commerce,

the sphereand "inFigure 2, D is the horizontal diam-' eter thereof. Theedges 610f the liner. approxnnate this diameter and preferably terminatebelow it, in order to insure a close contact of the liner whlch themajor part of.

the inside surface of the tube, otherwise the liner may separate anddrop down from the inside top of the tube unless Welded thereto.

and which I consider inadvisable. In. Figure l, I show the thin edges 6.depending. or flared from the true raidus, that is, the outer surface istangent to the circumference of the liner at the diameter D thereof. Thepurpose of the flared edges is that when the liner is pressed, driven orotherwise positioned in the tube, the said thin edges will give and bendinwardly and thus effect a tight hold or union with the tube, thecurvature of the tube at the edges functioning to thrust the linerupward to contact the tube.

In Figure 3 only two tubes of a series are shown in combination with aboiler, that number being thought sufiicient to show the relation of myimprovement with the boiler. 7 and 8 represent the respective boilerheads, and the tubes 5 are shown in a conventional engagement therewithas at 9. The liners 4 are of a length substantially that of the boilerbut less than that of the tube for two reasons, namely: To allow thetube to be expanded or flanged to position in the headin the usual way,and to allow a shouldered recess 10 so that any tool may be supported inthe recess to effect the driving of the liner connection with theaccompanying drawing the advantages of theconstructionand method ofoperation will be readily. understood by those skilled in the; arttowhich; the invention appertains, and while I have described theprinciple of operationg; to= gether with the device which I now considerto be the best embodiment thereof;- I- desire to have it understood thatthe device shown. is merely illustrative andttliat such, changes may bemade; whende's'ired asfallwithin the scope of the appended Claims.-

zxl-iliavingthus described my invention}.

what I! claim asnew and desire to seeureby lliett'ers Patent of theUnited States is the following 1.7 In. a boilen tubeconstruction; aliner comprising a; body: se ginentallin cross seb tion and having thin,flared edges a'dafpted tozholdfthe'linentiglitly in Contact with theinner'wall of the tube. QJIni a boiler tube constmCti on; a ores:-centi-shaped" liner: comprising a body of sizeand: length: a'dapt'ed t'osubstantially engage the maj on surface of} aboi-ler' tube,- said linerjhaving "thin; flaring edges adapted to lioldf the: liner; tightly" inoontaefi with the inner" walltzot the-tube.

.3..I n1 a: boiler tube construeti'oma;- liner iferen'oeoi. the tube,the 'body being relcomprising abody substantially segmental intransverse cross-section having an outside radius equal to that oftheinside of the tube and an' out-side circumference greater than one-halfof the inside circumatively thick at its midsection and thin at itsedges,-- and the edges being adapted to hold the liner tightly incontact with the inner'w-all of the tube; N

41 111 a boiler. tube construct-ion, aliner consisting" of atcrescent-shaped body rel ativ'ely thick at its" transversen'iidseefiio'il V and thin at its edges, the edges beingfiar'edoutwardly 25 little from the true outside rgnzll'ilfs of the body andextending" past" the? 45 diameter of the tube to effect a tight Hold ingof'tfieil-iner ilr'th'e" tuber; s In combination with a boil e'r and aretubest'here'0'f,- liners adafited to be driven into the'respectiw're"tubes,-- each? liner being of segmentel shape incrosse's'eetionj and of :11 length substantially that-of the toner;- andewe-H liner having filling flarin edges adapted to hold" the linertightly in- Contact with the" inner walloftli respective tube:

- In testimony" whereof I aflix my signs-

